66450728 has 16 divisors (see below), whose sum is σ = 125830260. Its totient is φ = 32896000.

The previous prime is 66450719. The next prime is 66450731. The reversal of 66450728 is 82705466.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 62378404 + 4072324 = 7898^2 + 2018^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66450691 and 66450700.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40313 + ... + 41928.

Almost surely, 2^66450728 is an apocalyptic number.

It is an amenable number.

66450728 is a deficient number, since it is larger than the sum of its proper divisors (59379532).

66450728 is a wasteful number, since it uses less digits than its factorization.

66450728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82348 (or 82344 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 38.

The square root of 66450728 is about 8151.7315951888. The cubic root of 66450728 is about 405.0418653059.

The spelling of 66450728 in words is "sixty-six million, four hundred fifty thousand, seven hundred twenty-eight".